If all the electric supply for a Boiling-Water Reactor (BWR) stops in consequence of a big earthquake or tsunami, water is provided into a reactor pressure vessel (RPV) to cool core fuel in the RPV. The enormous amount of water poured into the RPV could be contaminated by radionuclides leaked from the melted core fuel.
To clean the contaminated water, radionuclides in the contaminated water are adsorbed by adsorbent. The adsorbent after adsorbing radionuclides is presumed to adsorb radioactive cesium (137Cs) contained in the core fuel and presumed to emit high radiation. The adsorbent after adsorbing radionuclides is treated as radioactive waste and is needed to be solidified stably for long-term storage in a dedicated area for radioactive waste.
In a known solidification method of radioactive waste in Japanese patent publication No. 06-138298, a crushed inorganic ion exchange resin adsorbing cesium and/or strontium is pressure molded using a rubber press, and the molded resin is sintered in an atmospheric furnace at temperatures around 1200° C. The crushed inorganic ion exchange resin comprises composite moldenite, zeolite, or a mixture of them.
In another known solidification method of radioactive waste in Japanese patent publication No. 05-080197, a ceramic waste including a radioactive substance is filled in a metal capsule after an alkaline aqueous solution is added into the ceramic waste. The ceramic waste in the metal capsule is subjected to a hot hydrostatic pressurizing process to form a solidified body.